Magnetic ball joint for convertible stand/table

ABSTRACT

A magnetic ball joint, usable in connection with a convertible stand/table, as well as in other applications, utilizes an array of interleaved magnets and ferromagnetic bodies to both magnetically engage and retain a magnetically-attractive ball using concentrated magnetic force as well as to provide frictional resistance to movement of the ball in the joint.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to the following applications, each of whichfiled on even date herewith and incorporated by reference in itsentirety: U.S. patent application Ser. No. 14/308,609, filed by ChiShing Wong et al. and entitled “CONVERTIBLE STAND/TABLE;” and U.S.patent application Ser. No. 14/308,621, filed by Chi Shing Wong andentitled “LOCKING HINGE FOR CONVERTIBLE STAND/TABLE.”

BACKGROUND

Portable electronic devices have become increasingly popular for bothpersonal and commercial use. For example, tablet computers, or simplytablets, are increasing used for tasks such as surfing the internet,checking email, reading e-books, playing games, running apps, watchingvideo content, listening to audio content, and video conferencing, amongothers. Tablets, however, can be relatively heavy to hold, particularlyfor long periods of time, and with the increasing use of tablets, therehave been increasing incidents of pain and/or injury due to prolongedtablet use. Poor posture while using a tablet can lead to neck or backstrain, and extended holding of a tablet can lead to repetitive straininjuries in the arms and/or hands. Similar problems exist for othertypes of portable electronic devices such as electronic readers andmobile phones, as well as printed materials such as books, newspapersand magazines.

As a result of these concerns, some individuals rely on a tablet standor holder when using a tablet. A variety of tablet stand designs areavailable, including desktop and floor designs. Conventional tabletstands, however, suffer from a number of drawbacks. For example, manyconventional tablet stands are designed purely based upon mechanicalconcerns, rather than aesthetic concerns. In addition, given that floorstands are by necessity relatively large, such floor stands are noteasily hidden away when not in use, thus forcing some individuals toleave an unattractive floor stand sitting in their living space at alltimes. Some designs, in particular, are designed such that themechanical components that hold the tablet to the stand are effectivelyhidden behind the tablet when the tablet is held by the stand, and as aresult, some stand designs can be even less attractive when no tablet isheld by the stand.

In addition, given that an individual may wish to use a tablet in avariety of locations, many tablet stand designs are adjustable, e.g., toenable a tablet to be used while standing, while sitting in a chair,while sitting or laying on a sofa, or while sitting or laying in a bed.Adjustments to conventional tablet stand designs, however, are oftencumbersome and time consuming, since the adjustments may involve complexinteractions such as loosening and retightening adjustment knobs,extending or shortening variable length arms, etc. Furthermore, manyconventional designs enable users to adjust a stand to positions thatare not ergonomically acceptable, potentially leading to many of thesame concerns associated with hand-held tablets.

The manner in which a tablet is held by a stand may also be problematicin some designs. Many designs rely on opposing grips that retain atablet along one or more edges. While such designs can securely hold atablet, in practice such designs may be cumbersome to adjust toaccommodate multiple differently-shaped devices and/or may be difficultto insert or remove a tablet or other device.

Therefore, a substantial need exists in the art for a tablet standdesign that is aesthetically pleasing both when in use with a tablet andwhen not in use, that is easily adjustable between variousergonomically-friendly designs, and that can readily accept multipledifferently-shaped devices.

SUMMARY

The embodiments disclosed herein provide in one aspect a magnetic balljoint, usable in connection with a convertible stand/table, as well asin other applications, which utilizes an array of interleaved magnetsand ferromagnetic bodies to both magnetically engage and retain amagnetically-attractive ball using concentrated magnetic force as wellas to provide frictional resistance to movement of the ball in thejoint.

Therefore, consistent with one aspect of the invention, a magnetic balljoint may include a ball having an outer surface, at least a portion ofwhich is spherical and at least a portion of which ismagnetically-attractive, and a magnetic assembly including a pluralityof magnets and a plurality of ferromagnetic bodies interleaved with oneanother in an array to concentrate magnetic forces generally toward theball, at least a subset of the plurality of magnets and the plurality offerromagnetic bodies having substantially concave surfaces collectivelydefining at least a portion of a spherical cup substantially matching atleast a portion of the outer surface of the ball to magnetically engagethe ball.

Consistent with another aspect of the invention, an apparatus includes abase, an arm supported by the base and comprising a plurality of armsegments, a head including a top surface, and a magnetic ball jointpivotably mounting the head to the arm at an opposite end from the basesuch that the head is pivotable to a position inclined relative tohorizontal and configured to support a portable electronic device in anergonomically-suitable viewing position. The magnetic ball jointincludes a ball having an outer surface, at least a portion of which isspherical and at least a portion of which is magnetically-attractive,and a magnetic assembly including a plurality of magnets and a pluralityof ferromagnetic bodies interleaved with one another in an array toconcentrate magnetic forces generally toward the ball, at least a subsetof the plurality of magnets and the plurality of ferromagnetic bodieshaving substantially concave surfaces collectively defining at least aportion of a spherical cup substantially matching at least a portion ofthe outer surface of the ball to magnetically engage the ball.

These and other advantages and features, which characterize theinvention, are set forth in the claims annexed hereto and forming afurther part hereof. However, for a better understanding of theinvention, and of the advantages and objectives attained through itsuse, reference should be made to the Drawings, and to the accompanyingdescriptive matter, in which there is described example embodiments ofthe invention. This summary is merely provided to introduce a selectionof concepts that are further described below in the detaileddescription, and is not intended to identify key or essential featuresof the claimed subject matter, nor is it intended to be used as an aidin limiting the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a convertible stand/table consistentwith the invention in a stand configuration, with a tablet mountedthereto.

FIG. 2 is a left side elevational view of the convertible stand/table ofFIG. 1.

FIG. 3 is a cross-sectional view of a portion of the convertiblestand/table of FIG. 1, taken along lines 3-3 thereof.

FIG. 3A is an exploded perspective view of the ball joint referenced inFIG. 3, with portions of the head shown in phantom.

FIG. 3B is a cross-sectional view of the ball joint in FIG. 3, takenalong a central plane of the ball joint.

FIG. 3C is a cross-sectional view of the ball joint of FIG. 3, takenalong a plane that is laterally offset from the central plane of FIG.3B.

FIG. 4 is an exploded perspective view of a hinge from theconvertible/stand table of FIG. 1.

FIGS. 5A and 5B are schematic cross-sectional views of a hinge from theconvertible/stand table of FIG. 1, taken along lines 5A-5A thereof, andrespectively illustrating the hinge in locked and unlocked positions.

FIG. 5C is a schematic cross-sectional view of a hinge from theconvertible/stand table of FIG. 1, taken along lines 5C-5C thereof.

FIGS. 5D and 5E are opposing side elevational views of a hinge from theconvertible/stand table of FIG. 1, taken along lines 5A-5A thereof, withportions thereof cut away.

FIG. 6 is a partial perspective view of the convertible stand/table ofFIG. 1, illustrating use with a tablet.

FIG. 7 is a partial perspective view of the convertible stand/table ofFIG. 1, illustrating use with a book.

FIG. 8 is a partial perspective view illustrating in the configurationof the back of the head of the convertible stand/table of FIG. 1.

FIG. 9 is a left side elevational view of the convertible stand/table ofFIG. 1 in a table configuration.

FIG. 10 is a left side elevational view of the convertible stand/tableof FIG. 1 in a podium configuration.

FIG. 11 is a back elevational view of the head of the convertiblestand/table of FIG. 1, illustrating a monitor arm mount therefor.

DETAILED DESCRIPTION

Embodiments consistent with the invention are directed in part to aconvertible stand/table that is capable of being converted for usealternately as a table or a stand, and in particular, a stand suitablefor use in mounting, securing, holding, or otherwise retaining one ormore items for viewing and/or use by an individual. In the embodimentsdiscussed hereinafter, for example, focus is on a convertiblestand/table that may be used to retain a tablet (also referred to hereinas a “tablet computer”); however, it will be appreciated that aconvertible stand/table may also be used to retain alternatively and/oradditional items, including, for example, other types of portableelectronic devices such as mobile phones, electronic readers, etc., aswell as other types of non-electronic devices such as books, magazines,newspapers, music sheets, paper documents, etc. By virtue of theflexibility of the herein-described embodiments, a wide variety of itemsmay be retained in different embodiments, and accordingly, the inventionis not limited to the particular types of items that are retained by anyparticular embodiment of a convertible stand/table consistent with theinvention. Further, while the discussion hereinafter focuses on use witha tablet or tablet computer, it will be appreciated that a convertiblestand/table consistent with the invention may have use with a widevariety of other portable electronic devices, so the invention is notlimited as such.

As will become more apparent below, a convertible stand/table consistentwith the invention may be moved, adjusted or otherwise reconfiguredbetween a table configuration and a stand configuration. When in thetable configuration, a convertible stand/table presents a generallyhorizontal table surface capable of additionally retaining items, butgenerally using only gravity, rather than any additional retainingfunctionality. When in a stand configuration, however, items may beretained in a position suitable for presenting those items for useand/or viewing relative to a user's current position and/or orientation,e.g., when standing, sitting, reclining, laying down, etc., as well aswhen the user is sitting or laying down on various types of furniture,e.g., chairs, sofas, recliners, beds, etc. It will be appreciated thatwhen a convertible stand/table is configured in a table configuration,the convertible stand/table may function effectively as various types offurniture, e.g., a table, a side table, an end table, a nightstand, acoffee table, a food tray, a sitting desk, a standing desk, a breakfasttable, a plant stand, etc.

As will also become more apparent below, a convertible stand/tableconsistent with the invention may, in some embodiments, bereconfigurable between a plurality of ergonomically-suitable positions,thereby encouraging a user to use the convertible stand/table in amanner that is less likely to lead to pain and/or injury when viewing orusing an item retained by the convertible stand/table. In otherembodiments, no such restrictions may be made on the configurablepositions enabled by a convertible stand/table consistent with theinvention.

In addition, as will be discussed in greater detail below, a convertiblestand/table may incorporate one or more locking hinges that may beselectively released to adjust the convertible stand/table between aplurality of ergonomically-suitable positions. In some embodiments, eachlocking hinge relies on a mechanically-actuated magnetic clutch toselectively disengage first and second gears respectively coupled tofirst and second members and thereby selectively enable relativerotation between the first and second members about an axis of rotation,which in some embodiments are respectively coupled to arm segments of aconvertible stand/table. The mechanically-actuated magnetic clutchincludes first and second magnetic members disposed in an opposingrelationship, such that permanent magnets respectively disposed in eachmagnetic member may be placed into either a mutually attractive ormutually repellant relationship in response to relative movementtherebetween. One of the magnetic members is coupled to one of the gearsto move the gear along the axis of rotation and thereby selectivelydisengage or engage the gear from or with the other gear such that thegears are selectively engaged in response to mechanical movement of themagnetic members.

Furthermore, each locking hinge may, in some embodiments, be bothmechanically and remotely actuated, e.g., using a Bowden cable or othermechanical coupling between an actuator, e.g., a handle, disposed on ahead of a convertible stand/table, and a control member coupled to themagnetic clutch. By doing so, a user may be permitted in someembodiments to conveniently adjust the position of a convertiblestand/table by actuating a handle, adjusting the convertiblestand/table, and once a desired position is obtained, releasing thehandle to return each locking hinge to a locked configuration.

As will also become more apparent below, a convertible stand/table mayalso incorporate a magnetic ball joint to join a head of the convertiblestand/table to the end of an arm thereof. The magnetic ball jointdescribed hereinafter utilizes an array of interleaved magnets andferromagnetic bodies to both magnetically engage and retain amagnetically-attractive ball using concentrated magnetic force as wellas to provide frictional resistance to movement of the ball in thejoint.

Other modifications will be apparent to those of ordinary skill in theart having the benefit of the instant disclosure.

Turning now to the drawings, wherein like numbers denote like partsthroughout the several views, FIGS. 1-2 illustrate an example ofconvertible stand/table 10 (also referred to hereinafter as a “device”)consistent with the invention, and having mounted, secured or otherwiseretained thereon a tablet 12. Device 10 includes a base 14, arm 16 andhead 18. Base 14 is generally V-shaped with legs 22, 24 projectingforward of a rotatable arm mount 26 to which arm 16 is rotatably mountedto base 14. Rotatable arm mount 26 includes a fixed base portion 28 witha rotatable arm portion 30 configured to rotate relative to the fixedbase portion. In the illustrated embodiment, rotatable arm portion 30may be configured to rotate about an axis A (FIG. 2) that issubstantially vertical relative to a ground surface and the base, andover about a 60 degree range, e.g., about 30 degrees in each directionfrom the position illustrated in FIGS. 1-2. In some embodiments, one ormore detents may be incorporated into the rotatable arm mount torestrict free rotation of arm 16 within this range and/or a magneticarrangement may be used to reduce friction in the mount. For example, asingle detent may be provided in some embodiments proximate the centerof the range to resist rotation of the arm from a centered rotationalposition.

In some embodiments, arm 16 includes three segments 34, 36 and 38pivotably coupled to one another using a pair of hinges 40, 42. Hinges40, 42 respectively pivot about axes B and C, which in the illustratedembodiment are substantially parallel to one another as well as to aground surface. Hinge 40 is disposed at an opposite end of arm segment34 from rotatable arm mount 26, and in the illustrated embodiment, armsegment 34 is mounted at a fixed angular position to rotatable armportion 30 of rotatable arm mount 26 such that arm segment 34 is fixedat an angle α relative to axis A. In the illustrated embodiment, angle αis about 20 degrees, although other angles may be used in otherembodiments, and in still other embodiments, arm segment 34 may bepivotable relative to base 14.

As best illustrated in FIGS. 2-3 and 3A-3C, at the opposite end of armsegment 38 from hinge 42 is disposed a ball 44 configured to form a balljoint 46 with a cooperative socket 48 on the backside of head 18. Balljoint 46 is configured to permit head 18 to pivot in multiple directionsrelative to arm segment 38, and in some embodiments, may be configuredto restrict movement between only ergonomically-suitable positions. Asshown in FIG. 3, ball 44 may include an outer surface defining at leasta portion of a spherical body, and at least a portion of the outersurface may be formed of a magnetically-attractive material such assteel. A magnetic assembly 50 may be disposed within socket 48 andconfigured with a substantially concave surface suitable forcircumscribing a portion of ball 44 within socket 48 to attract ball 44and thereby magnetically engage ball 44 within socket 48 and providefrictional resistance to retain head 18 in a desired position selectedby a user.

As shown in FIG. 3A, In one embodiment, magnetic assembly 50 may includea plurality of permanent magnets 50 a-50 d and a plurality offerromagnetic bodies 51 a-51 d arranged in an array that concentrates oraugments the resulting magnetic field in a direction towards ball 44(thereby increasing the magnetic attraction with the ball), whilediminishing or canceling the magnetic field in a direction away from theball (i.e., outside of the ball joint). In the illustrated embodiment,magnets 50 a-50 d and bodies 51 a-51 d are arranged into a linear arrayof alternating and interleaved groups, with the outer body groupsrespectively including a single body 51 a and 51 b, and with the innerbody group including two coplanar plates 51 c/51 d and each magnet grouprespectively including two coplanar magnets (50 a/50 b, and 50 c/50 d).In some embodiments, the arrangement of magnets and/or ferromagneticbodies may utilize the Halbach effect to concentrate the magnetic forceapplied to the ball.

Magnets 50 a-50 d and bodies 51 a-51 d have a collective shape thatpresents a surface that conforms to that of ball 44; however, a pair ofnon-magnetic spacers 48 a, 48 b are defined in socket 48 (e.g.,integrally formed via injection molding/diecasting) and interposedbetween the ball and magnets 50 a-50 d such that magnets 50 a-50 d donot physically contact the outer surface of the ball. Bodies 51 a-51 d,however, do contact the outer surface of the ball when the ball isengaged by the magnet assembly. FIG. 3B, for example, is taken along acentral plane of the ball joint, which is also through plates or bodies51 c and 51 d, and it may be seen that each of these bodies is in directcontact with ball 44. FIG. 3C is laterally offset from the view of FIG.3B, and taken through magnets 50 c and 50 d, and it may be seen thatthese magnets do not physically contact ball 44, but are insteadseparated therefrom by spacer 48 b.

In the illustrated embodiment, for example, collectively each body 51a-51 d, along with spacers 48 a and 48 b, defines at least a portion ofa spherical cup (e.g., a hemispherical cup) configured to substantiallymatch and contact an outer surface of ball 44. Each body 51 a-51 d, aswell as each spacer 48 a, 48 b, therefore individually includes at leastone substantially concave surface that defines a portion of a sphericalzone for a sphere having substantially the same radius as ball 44, Eachmagnet 50 a-50 d also includes at least one substantially concavesurface that defines a portion of a spherical zone for a sphere;however, the radius of that sphere will have a somewhat larger radiusbased upon the thickness of spacers 48 a-48 b. It will be appreciatedthat any “sphere” defined by the bodies, magnets and/or spacers isgenerally defined by one or more substantially concave surfaces, and isconfigured to substantially match the corresponding sphere defined by asubstantially convex outer surface of the ball.

As noted above, magnets 50 a-d and bodies 51 a-d are interleaved andconfigured to define an array (e.g., based upon the Halbach effect) thatconcentrates or focuses the magnetic field toward the ball. Each magnet50 a-50 d is formed as a permanent magnet, e.g., made of NdFeB oranother suitable material for use as a permanent magnet. Each body 51a-d is formed from a ferromagnetic material such as iron or steel, butin the illustrated embodiment, is not itself a permanent magnet. Magnets50 a-50 d are magnetized across their respective thicknesses andinterposed between pairs of bodies 51 a-51 d, with the north polesthereof proximate to or facing bodies or plates 51 c and 51 d, and withthe south poles thereof proximate to or facing bodies 51 a and 51 b.Bodies 51 c and 51 d effectively short the magnetic field on the northpoles of all of the magnets, while bodies 51 a and 51 b short themagnetic field on the south poles of all of the magnets. Doing soeffectively concentrates and maximizes the magnetic fields along theinterfaces between bodies 51 c and 51 d and the magnets 50 a-50 d. Inother embodiments, the arrangement of magnetic poles may be reversed,such that the south poles of the magnets face bodies or plates 51 c and51 d.

It will also be appreciated that bodies 51 c/51 d and magnets 50 a/50 band 50 c/50 d in the illustrated embodiment are substantial mirrorimages of one another, and have the same polarity from the perspectiveof the array, but are otherwise physically separate from one another androughly half the length in a vertical direction as bodies 51 a and 51 b,in part to provide space through which a ball head screw may project(see below). In other embodiments, however, these pairs of bodies ormagnets may be replaced by single bodies or magnets that have a similarlength as bodies 51 a and 51 b, thereby reducing the number of bodiesand magnets to five. It will be appreciated that different numbers ofmagnets and/or bodies and/or orientations of magnets may be used inother embodiments.

In addition, it may be desirable in some embodiments to provide one ormore detents in ball joint 46 to facilitate positioning of the head inone or more desired, repeatable positions. For example, in theillustrated embodiment, and as shown in FIGS. 3, 3A and 3B, aspring-loaded ball head screw 52, serving as a pin, may project througha channel formed in magnetic assembly 50 such that a surface of thescrew is biased into contact with the surface of ball 44. Ball 44 maythen include one or more recesses or dimples 53 at predeterminedpositions such that, when the head is moved into a position in whichscrew 52 aligns with a dimple 53, the screw sinks into the dimple toprovide the user with feedback that a predetermined position has beenachieved, and movement away from that position is resisted based uponthe additional force required to overcome the spring bias of the screw.In one embodiment, for example, a dimple 53 may be located at a positionthat will level head 18 when convertible stand/table 10 is configured asa table.

It will be appreciated that a wide variety of alternate joints,including other ball joint designs, may be used to secure head 18 to armsegment 38. For example, ball joint designs that restrict rotation aboutthe axis of arm segment 38 may be used, as may ball joint designs thatrestrict movement only in predetermined directions (e.g., along anx-axis and/or a y-axis), may be used. In addition, other mechanisms forvarying the freedom of movement for head 18 may be used, including, forexample, a user accessible adjustment knob that may be used to loosenthe ball joint to permit user adjustment of the head and thereaftertighten the ball joint to secure the head in a fixed position. Otheralternatives, including various frictional, magnetic, tensioned or otherarrangements, will be apparent to one of ordinary skill in the arthaving the benefit of the instant disclosure.

Hinges 40, 42 in the illustrated embodiment are locking hinges that arenormally biased to a locked configuration that restricts any relativemovement between their respective arm segments within a range of angularpositions, and that may be selectively actuated to an unlockedconfiguration that permits relative movement between those respectivearm segments. In the illustrated embodiment, hinges 40, 42 arereleasable via an arm release 54 including a handle 56 that is pivotablefrom the normally-biased position illustrated in FIGS. 2-3 toward a topsurface of head 18, e.g., by a user pulling the handle forward whilefacing head 18. In this manner, a user is able to adjust all three armsegments 34-38 of arm 16 at the same time by actuating handle 56,adjusting the arm segments and then releasing handle 56 when the armsegments are properly positioned.

As illustrated in FIG. 3, arm release 54 may be coupled to hinges 40, 42using one or more flexible Bowden cables 58, each including an outersleeve 60 and an inner wire 62 that slides within outer sleeve 60. Innerwire 62 projects around a pulley 64 and is secured to handle 56 within aslot 66. Inner wire 62 extends along a cam surface 68 formed on handle56 such that, when the handle is pivoted in the direction of arrow 70,inner wire 62 is pulled in the direction of arrow 72. Outer sleeve 60 isretained in a fixed position against a ledge 74 formed proximate aclamping arrangement defined by opposing members 76, 78 of a rear panel80 of head 18, such that when handle 56 is actuated by the user, innerwire 62 will slide within outer sleeve 60.

While only one cable 58 is illustrated in FIG. 3, it will be appreciatedthat separate cables may be used to actuate hinges 40, 42, with bothcables secured to handle 56 and actuated at the same time through thesame movement of the handle. In other embodiments, only one cable may beused, and in some embodiments, the hinges may be separately actuated topermit one hinge to be actuated at a time.

Now turning to FIGS. 4 and 5A-5E, an example implementation of a lockinghinge 100 is illustrated in greater detail, it being understood thathinge 100 may be used for each of hinges 40, 42 in convertiblestand/table 10 of FIGS. 1-3. Hinge 100 in the illustrated embodimentforms an angular indexing adjustable joint with a mechanically-actuatedmagnetic clutch. In the illustrated embodiment, hinge 100 provides asingle action actuation from a long distance and with bidirectionalrotational position locking and release, and doing so within a limitedspace, under heavy loading and with a relatively fine grained range ofangular locking intervals (e.g., less than about 12 degrees).

In contrast with other hinge designs, e.g., locking pin arrangements,secondary locking arrangements, electromagnetic locking arrangements,unidirectional locking arrangements, and friction brake lockingarrangements, the herein-described locking hinge addresses concernsassociated with long moment arms, bi-directional freedom of movement,fine grained locking within a range of movement, small spacerequirements, and remote actuation, and does so without requiring asource of electrical power.

Hinge 100 includes first and second members, which in the illustratedembodiment are housings 102, 104, each having a sleeve portion 106, 108configured to slide into the end of a respective arm segment (which maybe hollow in the illustrated embodiments). Each housing 102, 104 alsoincludes offset cylindrical portions 110, 112 that mate along annularsurfaces 114, 116 to provide for relative rotation of the housings aboutan axis of rotation 118. An annular ring 120 is integrally formed withinan interior of cylindrical portion 110 of housing 102 to partition theinterior into inner and outer portions 122, 124. Likewise, an annularring 126 is integrally formed within an interior of cylindrical portion112 of housing 104 to partition the interior into inner and outerportions 128, 130.

A magnetic clutch 132 is used to selectively engage and disengage a pairof gears that are respectively coupled to the first and second housings,and that oppose one another along axis of rotation 118 by moving one ofthe gears generally along the axis of rotation between first and secondgear positions. The first gear position is a position in which the gearsare intermeshed with one another to restrict relative rotation betweenthe housings, and the second gear position is one in which the gears areaxially separated from one another along the axis of rotation to allowfor relative rotation between the first and second housings.

In the illustrated embodiment, magnetic clutch 132 is housed withinrespective inner portions 122, 128 of housings 102, 104 and includes apair of magnetic members disposed in an opposing relationship, with onemagnetic member being movable relative to the other magnetic memberbetween first and second clutch positions, and with the other magneticmember coupled to one of the gears to move the gear between the firstand second gear positions. When in the first clutch position, themagnetic members are mutually repellant to move, urge or otherwise applya force to the gear into the first gear position to restrict relativerotation between the first and second housings. When in the secondclutch position, on the other hand, the magnetic members are mutuallyattractive such that the gear is moved, urged, or otherwise forced intothe second gear position to allow for relative rotation between thefirst and second housings.

In the illustrated embodiment, the magnetic members are implemented as amagnetic drive wheel 134 and magnetic gear wheel 136, each having anannular array of recesses 138, 140 configured to retain a plurality of(e.g., 12) permanent magnets 142, 144 (magnets 142 are illustrated inFIG. 4 installed within recesses 138, while magnets 144 are illustratedin exploded form). Magnets 142, 144 are substantially equally spaced andarranged in an alternating fashion to provide alternating north andsouth polarities around the circumference of each wheel 134, 136, suchthat rotation of drive wheel 134 about axis 118 will alternately orientopposing magnets 142, 144 in mutually attractive or repellentrelationships. Various types of permanent magnets, including for examplerare earth magnets, ferromagnets, composite magnets, ceramic magnets,etc. may be used. In addition, greater or fewer numbers of magnets(e.g., a few as one magnet) may be used on each magnetic member in otherembodiments. For example, one or both of wheels 134, 136 may include asingle ceramic magnetic disk instead of an annular array of magnets.

Thus, in the illustrated embodiment, the first and second clutchpositions are angular positions about the axis of rotation. In otherembodiments, however, magnetic members may be movable relative to oneanother in other manners, e.g., through linear movement of a pair ofmagnetic members relative to one another.

A bushing 146 is received within each of inner portions 122, 128, and anaxle 148 projects through cylindrical portions 110, 112 and thecomponents of magnetic clutch 132. Axle 148 extends along rotationalaxis 118, and includes a head 150 with a tab 152 and threeaxially-separated portions 154, 156 and 158. Portion 154 is keyed (e.g.,using a hexagonal cross-section) to receive a complementary keyedchannel 160 defined in magnetic gear wheel 136 and thereby restrictrotation of magnetic gear wheel 136 relative to axle 148. As will becomemore apparent below, portion 154 is of sufficient length to allowmagnetic gear wheel 136 to move axially between engaged and disengagedpositions along axis 118.

Portion 156 has a smaller diameter than portion 154, but is also keyed(e.g., using a hexagonal cross-section) to receive a complementary keyedchannel 162 (FIG. 5C) defined through annular ring 126 of housing 104 tolikewise restrict rotation of the axle relative to housing 104, and assuch, axle 148, magnetic gear wheel 136 and housing 104 are rotationallyfixed relative to one another and are all capable of rotating relativeto housing 102 when magnetic clutch 132 disengages the pair of gears.

Portion 158 of axle 148 may be of an even smaller diameter, and may bethreaded to engage a threaded lock ring 164 (which is separated axiallyfrom housing 104 by a spring washer 166) when the components of hinge100 are assembled together. Axle 148 may also be retained within hinge100 in other manners that will be appreciated by one of ordinary skillin the art having the benefit of the disclosure, e.g., via a cotter pin.Covers 168, 170 may also be provided to cover the internal components ofhinge 100 and provide an aesthetically pleasing design.

As shown in FIGS. 4 and 5C, axle 148 has an opening or channel 151extending between the opposing sides of the hinge. In some embodiments,it may be desirable to route a power cable (e.g., power cable 222 ofFIG. 3) and/or a Bowden cable 58 through channel 151 such that thecable(s) may extend through the interiors of the respective arm segmentscoupled to housings 102, 104. Returning to FIGS. 1-2, for example, itwill be appreciated that it may be desirable to route power cable 222through both hinges 40, 42, and additionally route the Bowden cable 58for hinge 40 through hinge 42. Referring to FIG. 4, the Bowden cable 58may be routed, for example, into housing 104, into channel 151 of axle148 at the end proximate lock ring 164, out of channel 151 proximatehead 150 of axle 148 and into housing 102.

As shown in FIGS. 4 and 5E, tab 152 on axle 148 may be used to restrictthe range of motion for hinge 100 by incorporating into outer portion124 of housing 102 an annular track 171 defined by opposing shouldersformed in outer portion 124 that engage tab 152 at predetermined angularpositions and restrict further rotation beyond such positions.

As noted above, a pair of gears are used to selectively restrictrelative rotation between housings 102, 104. In the illustratedembodiment, these gears are integrated respectively onto annular ring120 and magnetic gear wheel 136 of magnetic clutch 132. In particular,as is also shown in FIG. 4, magnetic gear wheel 136 includes an annulararrangement of teeth 172 (e.g., 30 teeth) on an opposite face to thatwhich faces magnetic drive wheel 134 such that the teeth 172 project inan opposite direction along the axis of rotation from the magnetic drivewheel. Teeth 172 are configured to mate with a complementary annulararrangement of teeth 174 formed on an inwardly-facing surface of annularring 120. In the illustrated embodiment, teeth 172, 174 expand outradially from axis 118, but are configured to mate face to face whenmagnetic gear wheel 136 is repelled by magnetic drive gear 134.

It will be appreciated, however, that in other embodiments, differentgear arrangements may be used. For example, gears may be separatelydefined from magnetic gear wheel 136 and/or annular ring 120, andcoupled thereto via linkages, shafts, control rods, or other mechanicalarrangements. As such, the invention is not limited to implementationswhere the gears are integrated into a housing and/or a component of amagnetic clutch.

Actuation of hinge 100, as noted above, is initiated in response toactuation of handle 56 (FIGS. 2-3), which retracts inner wire 62 ofcable 58 out of hinge 100. Wire 62 is coupled to a control member 176having disposed at a distal end thereof a control pin 178 that projectsin a direction generally parallel to axis 118 and that engages a recess180 formed in magnetic drive wheel 134 to translate linear movement ofinner wire 62 into rotational movement of magnetic drive wheel 134. Ofnote, magnetic drive wheel 134 is not keyed to axle 148, and as such ispermitted to rotate freely relative to the axle. Outer sleeve 60 ofcable 58 is secured to hinge 100 by a cable mount 182, and a spring 184biases control member 176 to a position that effectively locks thehinge. It will be appreciated that in other embodiments, alternatearrangements to a linearly-moveable control member may be used, e.g., arotationally-movable control arrangement.

In operation, and as illustrated in particular in FIG. 5A, when hinge100 is in a locked state, control member 176 is biased to the left sideof the figure, which rotates magnetic drive wheel 134 to the positionillustrated in FIG. 5A. In this position, magnets 142, 144 are in amutually repellant position with magnets of like polarity opposing oneanother. As such, magnetic gear wheel 136 is biased away from magneticdrive wheel 134 (as represented by gap 186) such that teeth 172 and 174on magnetic gear wheel 136 and housing 102 mesh with one another andprevent relative rotation therebetween. With magnetic gear wheel 136keyed to axle 148, which is in turn keyed to housing 104, relativerotation of housings 102, 104 of hinge 100 is restricted, therebylocking the hinge.

Then, as illustrated in FIG. 5B, when inner wire 62 of cable 58 isretracted from hinge 100 as represented by arrows 188, control pin 178moves in the direction represented by arrow 190, thereby rotatingmagnetic drive wheel 134 to a position where the opposing magnets 142,144 are in a mutually attractive position with magnets of oppositepolarity opposing one another. As such, magnetic gear wheel 136 isattracted to magnetic drive wheel 134, thereby disengaging teeth 172from teeth 174 on housing 102 and allowing for relative rotation betweenhousings 102, 104 about axis 118, thereby releasing or unlocking thehinge.

Thereafter, upon release of handle 56 (FIGS. 2-3), magnetic drive wheel134 rotates back to the position illustrated in FIG. 5A, and sincemagnetic gear wheel 136 is keyed to housing 104, wheels 134, 136 willonce again be in a mutually repellant state, and teeth 172 of magneticgear wheel 136 will reengage with teeth 174 of housing 102, once againlocking the hinge.

Returning now to FIGS. 1-2, it should be noted that hinges 40, 42 may besecured to arm segments 34-38 using screws, bolts or other fastenerswith the sleeve portions thereof fitted into the respective armsegments. Other fastening arrangements may be used in other embodimentsconsistent with the invention.

Head 18 in the illustrated embodiment has a roughly triangular shapewith rounded corners and includes a front or top surface 82 formed of amagnetically-attractive surface (i.e., a surface to which a magnet maybe attached) such as a surface material (e.g., melamine) laminated to aniron filled rubber sheet, steel, etc. One or more ledges 84 may extendoutwardly from a bottom edge of head 18 to support a tablet, otherelectronic device, book or other item. In addition, a removable, stopper86, having a magnetic material applied thereto, may bemagnetically-retained on head 18 to assist with supporting an item onthe surface of the head.

In addition, as illustrated in FIG. 6, it may be desirable in someembodiments to utilize a mounting pad 88 to mount tablet 12 or any othersuitable item to head 18. In the illustrated embodiment, mounting pad 88is formed from multiple layers 90, 92 adhered to one another, e.g.,through the use of adhesive. Layer 90, which faces head 18, is amagnetic layer formed, for example, from a flexible rubber magnetcompound material such as the Y11-07 material available from AICEngineering Ltd., among other materials. Layer 90 therefore includes atleast one permanent magnet and provides magnetic attraction to topsurface 82 of head 18. It will be appreciated that in other embodiments,top surface 82 may be magnetized via permanent magnets or throughelectromagnetism, and layer 90 may not be magnetized but instead may beformed from a magnetically-attractive material.

Layer 92 is a microsuction layer formed, for example, from a flexiblemicrosuction material such as the Regabond-S material available from CBCCo. Ltd., among other materials such as polyurethane. Layer 92 forms asuction cup surface that adheres to the back of tablet 12, and as such,other surfaces, e.g., using one or more distinct suction cups or anarray of suction cups may be used as an alternative to a microsuctionlayer in some embodiments. In still other embodiments, an adhesive layermay be used as an alternative for adhering the mounting pad to thetablet.

In use, mounting pad 88 is mounted to tablet 12 in a semi-permanentmanner, with the microsuction layer 92 of mounting pad 88 adhering tothe back of the tablet. By virtue of mounting pad 88 being of arelatively thin construction, the pad may be kept on the tablet evenwhen not used with convertible stand/table 10. As a result, whenever itis desirable to use the convertible stand/table with the tablet, a userneed only place the tablet on top surface 82, and the magneticattraction between magnetic layer 90 and top surface 82 will assist withholding tablet 12 on the top surface.

Mounting pad 88 may differ in size for different types of items, e.g.,smaller for mobile phones, and in some embodiments may take shapes otherthan the circular shape illustrated in FIG. 6. In addition, each layer90, 92 may be implemented in other manners, and in some embodiments,layers 90, 92 may be combined, e.g., by embedding iron filings in amicrosuction material.

It will be appreciated that a consumer may purchase or be provided withmultiple mounting pads that can be adhered to multiple tablets or otheritems, such that a convertible stand/table may be used with multipleitems at the same time and/or at different times. In addition, it willbe appreciated that a tablet or other item may be magnetically mountedon head 18 in other manners. For example, a tablet may be mounted withina case having a magnetic back, or a magnetic surface may be integratedinto an item itself.

Next, as illustrated in FIG. 7, additional items, e.g., a book 200, maybe retained on head 18. Book 200 may be supported by edges 84, and insome embodiments, one or more elastic retaining bands 202, 204 may beused to further retain the book on the head. Further, in someembodiments it may be desirable to provide one or more reading lights206 (e.g., flexible LED lights) to illuminate the top surface, and thusa book disposed thereon, for use under low light conditions.

As illustrated in FIG. 8, and with additional reference to FIG. 3, aback side of head 18 may define a rear surface of the head and beprovided with a number of additional features to facilitate theaforementioned functionality. For example, recessed channels 208 may beprovided on head 18 to store bands 202, 204 when not in use, and one ormore enlarged areas 210 may be provided in recesses 208 to facilitategrasping of the bands 202, 204 when stored in the recesses. Each bandforms a loop that extends partially through an interior of head 18,passing through an aperture proximate lower end 212 of each recess 208,as well as passing through a slot 216 proximate the upper end 214 ofeach recess 208. A set of notches 218 are disposed proximate to slot 216to anchor the respective band 202, 204 at one of a plurality ofpositions along a top edge 219 of the head to restrict the band 202, 204from shifting along the top surface of the head. As such, whenever it isdesirable to use bands 202, 204 when the bands are stored in slots 208,a user may grab each band and pull it around to the front of head 18 andover the corners of a book or other item. Furthermore, a user may moveeach band to one of the notches 18 to position each band to a desiredposition.

In addition, it may be desirable to provide one or more power ports 220,e.g., powered USB-compatible ports, for use in charging items while theitems are being used with convertible stand/table 10. In addition, asillustrated in FIG. 8, a power port 220 may serve a secondary functionof retaining reading light 206. Power to power ports 220 may be providedin the illustrated embodiment by a power cable 222, which extendsthrough the interior of head 18, exits an opening 224 formed in rearpanel 80, and as illustrated in FIGS. 1-3, enters opening 224 of armsegment 38, extends through each arm segment 34-38, each hinge 40, 42,and mount 26, and finally exits mount 26 on base 14, terminating at aconnector 226. Cable 222 may be a USB-compatible cable, or in thealternative, may merely provide a suitable source of AC or DC power thatis converted to a USB-compatible format by on-board circuitry (notshown) prior to being supplied to power ports 220. Connector 226 may besuitable for connecting, for example, to one or more types of wallchargers/power adapters, e.g., to support the domestic powerrequirements of various countries around the world.

In other embodiments, cable 222 may enter and/or exit one or more armsegments, e.g., to bypass a hinge 40, 42, or may not be routed throughany portion of arm 16 at all. In still other embodiments, one or morereleasable connectors may be provided along cable 222, e.g., when it isdesirable to fully separate head 18 from the remainder of convertiblestand/table 10. Other modifications will be apparent to one of ordinaryskill in the art having the benefit of the instant disclosure.

Returning again to FIG. 8, it may also be desirable in some embodimentsto provide one or more recessed holders, e.g., holders 228, 230 in theback of head 18. Holder 228 may be configured, for example, to store oneor more stoppers 86 while not in use, while holder 230 may be configuredto store reading light 206 when not in use.

It will be appreciated that more or fewer holders may be provided onhead 18, and that such holders may be specifically configured to storedifferent kinds of items. It will also be appreciated that in someembodiments, head 18 may omit various of the aforementioned features,and may lack, for example, power ports, recessed holders, and/orretaining bands. Furthermore, in other embodiments, head 18 mayincorporate other features, e.g., one or more movable members capable ofincreasing the effective size of head 18 to support larger items. Forexample, as illustrated in phantom in FIG. 8, it may be desirable toprovide one or more rotatable “antennae” 232 capable of being pivoted toa position such as illustrated at 232′ to support larger items on head18. Other types of movable members, including slidable members normallyrecessed within the interior of head 18, may also be used. Othermodifications will be apparent to one of ordinary skill in the arthaving the benefit of the instant disclosure.

Now turning to FIG. 9, as noted above convertible stand/table 10 isconvertible between at least a stand configuration and a tableconfiguration. A typical stand configuration of convertible stand/table10 is illustrated in FIGS. 1-2, while FIG. 9 illustrates a typical tableconfiguration where arm segments 34-38 are fully collapsed and extendingsubstantially parallel to one another via hinges 40, 42 to form the baseof a table, with head 18 pivoted on ball mount 46 to present as a tabletop a substantially horizontal upper surface 82 of head 18 upon whichitems may be placed. As noted above, a user may be assisted in orientingthe head in this position through the use of a detent arrangement inball mount 46.

In the illustrated embodiment, for example, in this configuration uppersurface 82 may be about 26 inches (about 66 cm) from the floor. It willbe appreciated that differing dimensions may be used in someembodiments, and further that a table configuration may be provided evenwhen arm segments 34-38 are not fully collapsed onto one another, e.g.,to vary the height of the table top. In still other embodiments, one ormore of arm segments 34-38 may have a variable length to allow formultiple table heights.

While FIG. 9 illustrates a collapsed position suitable for use in atable configuration, FIG. 10 illustrates an extended position ofconvertible stand/table 10 in which all arm segments 34-48 are collinearwith one another, which may be suitable for use, for example, in apodium or music stand configuration, which may be used, for example, tohold a tablet, sheet music, book or other item suitable for use whenspeaking, singing or playing music.

It will be appreciated that a multitude of other configurations may besupported through the separate configuration of hinges 40, 42, ballmount 46 and mount 26, e.g., for use when standing, sitting, reclining,laying down, etc., as well as when the user is sitting or laying down onvarious types of furniture, e.g., chairs, sofas, recliners, beds, etc.Additional or fewer joints, hinges, mounts, etc. may be used indifferent embodiments to either expand or restrict the range ofconfigurations supported. In some embodiments, for example, it may bedesirable to restrict the range of configurations to excludeergonomically-unsuitable reading positions and/or to restrict theinclination of the head to reduce the risk of items falling off (e.g.,to maintain the inclination at least about 10-20 degrees offset fromvertical).

In addition, in some embodiments it may be desirable to utilize the headof a convertible stand/table separate from the base and arms thereof. Asshown in FIG. 8, for example, rear panel 80 of head 18 may be removablysecured to head 18, e.g., using one or more threaded fasteners 234 asillustrated in FIG. 8. In the alternative, releasable tabs or catches orother releasable or removable configurations may be used to secure therear panel to the head. Furthermore, as shown in FIG. 11, it may bedesirable in some embodiments to provide inside of head 18, e.g., withina recess 240 normally covered by rear panel 80, a monitor or TV mountincluding a plurality of tapped holes 242 disposed at the ends ofpedestals 244 and arranged in an industry-standard configuration, e.g.,any of the VESA mounting standards defined by the Video ElectronicsStandards Association (VESA).

By doing so, a user may detach head 18 from the remaining components ofconvertible stand/table 10, and attach the head to a standard TV/monitormount, e.g., a wall mount, a ceiling mount, a desk/table mount, etc. Asnoted above, it may also be desirable in such circumstances to providereleasable connectors to enable the power cable to be disconnected. Inother embodiments, the power ports may be integrated into rear panel 80,or all of the necessary power components may be integrated into head 18,thereby eliminating the need to disconnect the power ports from thepower cable. In addition, in some embodiments, a consumer may even beable to purchase head 18 as a separate component without the remainingcomponents of convertible stand/table 10.

In still other embodiments, rear panel 80 may be configured to functionin much the same manner as a TV/monitor mount, and may therefore includea VESA-compatible set of holes suitable for mounting to a TV or monitorsuch that, when head 18 is removed, a TV or monitor may be mounted torear panel 80, with base 14 and arm 16 supporting the TV or monitor in asimilar manner to head 18. As another alternative, the rear panel may besecurable to an additional adapter that includes a VESA-compatible setof holes suitable for mounting to a TV or monitor. The adapter, in sucha configuration, may have a similar hole pattern to head 18 such thatrear panel 80 may be secured to the adapter using the same fastenersused to secure rear panel 80 to head 18.

While particular embodiments have been described, it is not intendedthat the invention be limited thereto, as it is intended that theinvention be as broad in scope as the art will allow and that thespecification be read likewise. It will therefore be appreciated bythose skilled in the art that yet other modifications could be madewithout deviating from its spirit and scope as claimed.

What is claimed is:
 1. A magnetic ball joint, comprising: a ball having an outer surface, at least a portion of which is spherical and at least a portion of which is magnetically-attractive; and a magnetic assembly including a plurality of magnets and a plurality of ferromagnetic bodies interleaved with one another in an array to concentrate magnetic forces generally toward the ball, at least a subset of the plurality of magnets and the plurality of ferromagnetic bodies having substantially concave surfaces collectively defining at least a portion of a spherical cup substantially matching at least a portion of the outer surface of the ball to magnetically engage the ball.
 2. The magnetic ball joint of claim 1, further comprising at least one non-magnetic spacer having a substantially concave surface defining at least a portion of the spherical cup and interposed between the ball and at least one of the plurality of magnets.
 3. The magnetic ball joint of claim 2, wherein the at least one of the plurality of magnets between which the non-magnetic spacer is interposed has a substantially concave surface defining at least a portion of a spherical zone having a radius that is greater than that of the spherical cup.
 4. The magnetic ball joint of claim 1, wherein the plurality of magnets and the plurality of ferromagnetic bodies are arranged in a substantially linear array.
 5. The magnetic ball joint of claim 4, wherein the plurality of ferromagnetic bodies includes first, second and third ferromagnetic bodies, wherein the plurality of magnets includes first and second magnets, and wherein the first magnet is interposed between the first and second ferromagnetic bodies and the second magnet is interposed between the second and third ferromagnetic bodies.
 6. The magnetic ball joint of claim 5, wherein the first and second magnets are each magnetized across their respective thicknesses, and wherein north poles of the first and second magnets are disposed proximate the second ferromagnetic body and south poles of the first and second magnets are respectively disposed proximate the first and third ferromagnetic bodies, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second ferromagnetic body and the first and second magnets.
 7. The magnetic ball joint of claim 5, wherein the first and second magnets are each magnetized across their respective thicknesses, and wherein south poles of the first and second magnets are disposed proximate the second ferromagnetic body and north poles of the first and second magnets are respectively disposed proximate the first and third ferromagnetic bodies, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second ferromagnetic body and the first and second magnets.
 8. The magnetic ball joint of claim 4, wherein the plurality of ferromagnetic bodies includes first, second, third and fourth ferromagnetic bodies, wherein the second and third ferromagnetic bodies are substantially coplanar, wherein the plurality of magnets includes first, second, third and fourth magnets, wherein the first and second magnets are substantially coplanar and the third and fourth magnets are substantially coplanar, and wherein the first and second magnets are interposed between the first ferromagnetic body and the second and third ferromagnetic bodies and the third and fourth magnets are interposed between the second and third ferromagnetic bodies and the fourth ferromagnetic body.
 9. The magnetic ball joint of claim 8, wherein the first, second, third and fourth magnets are each magnetized across their respective thicknesses, and wherein north poles of the first, second, third and fourth magnets are disposed proximate the second and third ferromagnetic bodies, south poles of the first and second magnets are disposed proximate the first ferromagnetic body, and south poles of the third and fourth magnets are disposed proximate the fourth ferromagnetic body, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second and third ferromagnetic bodies and the first, second, third and fourth magnets.
 10. The magnetic ball joint of claim 8, wherein the first, second, third and fourth magnets are each magnetized across their respective thicknesses, and wherein south poles of the first, second, third and fourth magnets are disposed proximate the second and third ferromagnetic bodies, north poles of the first and second magnets are disposed proximate the first ferromagnetic body, and north poles of the third and fourth magnets are disposed proximate the fourth ferromagnetic body, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second and third ferromagnetic bodies and the first, second, third and fourth magnets.
 11. The magnetic ball joint of claim 1, further comprising: a housing configured to house the plurality of magnets; and at least one detent, the detent including a dimple defined in the outer surface of the ball and a pin coupled to the housing and biased against the outer surface of the ball to selectively engage the dimple when the ball is in a predetermined position relative to the plurality of magnets.
 12. An apparatus, comprising: a base; an arm supported by the base and comprising a plurality of arm segments; a head including a top surface; and a magnetic ball joint pivotably mounting the head to the arm at an opposite end from the base such that the head is pivotable to a position inclined relative to horizontal and configured to support a portable electronic device in an ergonomically-suitable viewing position, wherein the magnetic ball joint comprises: a ball having an outer surface, at least a portion of which is spherical and at least a portion of which is magnetically-attractive; and a magnetic assembly including a plurality of magnets and a plurality of ferromagnetic bodies interleaved with one another in an array to concentrate magnetic forces generally toward the ball, at least a subset of the plurality of magnets and the plurality of ferromagnetic bodies having substantially concave surfaces collectively defining at least a portion of a spherical cup substantially matching at least a portion of the outer surface of the ball to magnetically engage the ball.
 13. The apparatus of claim 12, wherein the ball is coupled to the arm and the magnetic assembly is coupled to the head.
 14. The apparatus of claim 12, further comprising at least one non-magnetic spacer having a substantially concave surface defining at least a portion of the spherical cup and interposed between the ball and at least one of the plurality of magnets, wherein the at least one of the plurality of magnets between which the non-magnetic spacer is interposed has a substantially concave surface defining at least a portion of a spherical zone having a radius that is greater than that of the spherical cup.
 15. The apparatus of claim 12, wherein the plurality of magnets and the plurality of ferromagnetic bodies are arranged in a substantially linear array, wherein the plurality of ferromagnetic bodies includes first, second and third ferromagnetic bodies, wherein the plurality of magnets includes first and second magnets, wherein the first magnet is interposed between the first and second ferromagnetic bodies and the second magnet is interposed between the second and third ferromagnetic bodies, wherein the first and second magnets are each magnetized across their respective thicknesses, and wherein north poles of the first and second magnets are disposed proximate the second ferromagnetic body and south poles of the first and second magnets are respectively disposed proximate the first and third ferromagnetic bodies, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second ferromagnetic body and the first and second magnets.
 16. The apparatus of claim 12, wherein the plurality of magnets and the plurality of ferromagnetic bodies are arranged in a substantially linear array, wherein the plurality of ferromagnetic bodies includes first, second and third ferromagnetic bodies, wherein the plurality of magnets includes first and second magnets, wherein the first magnet is interposed between the first and second ferromagnetic bodies and the second magnet is interposed between the second and third ferromagnetic bodies, wherein the first and second magnets are each magnetized across their respective thicknesses, and wherein south poles of the first and second magnets are disposed proximate the second ferromagnetic body and north poles of the first and second magnets are respectively disposed proximate the first and third ferromagnetic bodies, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second ferromagnetic body and the first and second magnets.
 17. The apparatus of claim 12, wherein the plurality of magnets and the plurality of ferromagnetic bodies are arranged in a substantially linear array, wherein the plurality of ferromagnetic bodies includes first, second, third and fourth ferromagnetic bodies, wherein the second and third ferromagnetic bodies are substantially coplanar, wherein the plurality of magnets includes first, second, third and fourth magnets, wherein the first and second magnets are substantially coplanar and the third and fourth magnets are substantially coplanar, and wherein the first and second magnets are interposed between the first ferromagnetic body and the second and third ferromagnetic bodies and the third and fourth magnets are interposed between the second and third ferromagnetic bodies and the fourth ferromagnetic body.
 18. The apparatus of claim 17, wherein the first, second, third and fourth magnets are each magnetized across their respective thicknesses, and wherein north poles of the first, second, third and fourth magnets are disposed proximate the second and third ferromagnetic bodies, south poles of the first and second magnets are disposed proximate the first ferromagnetic body, and south poles of the third and fourth magnets are disposed proximate the fourth ferromagnetic body, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second and third ferromagnetic bodies and the first, second, third and fourth magnets.
 19. The apparatus of claim 17, wherein the first, second, third and fourth magnets are each magnetized across their respective thicknesses, and wherein south poles of the first, second, third and fourth magnets are disposed proximate the second and third ferromagnetic bodies, north poles of the first and second magnets are disposed proximate the first ferromagnetic body, and north poles of the third and fourth magnets are disposed proximate the fourth ferromagnetic body, whereby a magnetic field of the magnetic assembly is maximized along interfaces between the second and third ferromagnetic bodies and the first, second, third and fourth magnets.
 20. The apparatus of claim 12, further comprising: a housing configured to house the plurality of magnets; and at least one detent, the detent including a dimple defined in the outer surface of the ball and a pin coupled to the housing and biased against the outer surface of the ball to selectively engage the dimple when the ball is in a predetermined position relative to the plurality of magnets. 